With the continuous development of the wind power generation technology, wind generator sets have now been widely used. Under certain conditions, a limited power control may be applied to a wind generator set. The limited power control may be understood as that when a torque of the wind generator set reach a rated torque, constant power output of the wind generator set is realized through pitch control.
At present, there is no effective identification apparatus or method for blade icing states under the limited power condition. However, it has become an ordinary state that wind generator sets operate under the limited power condition in some of wind farms, and meanwhile in winter, there are a large number of blades iced up in the wind farms.